Additive manufacturing processes such as selective laser sintering have enabled rapid prototyping and production of objects with complex shapes in a wide variety of materials. Direct sintering of technical ceramics using additive manufacturing processes is much more difficult than processing of polymers and metals. Ceramics generally sinter at higher temperatures, and sintering rates of technical ceramics are usually limited by relatively slow solid state diffusion-based kinetics. Direct sintering in additive manufacturing requires rapid kinetics. In addition, ceramics are typically brittle and fracture easily due to thermally or mechanically induced stress and strain. Because of these issues, additive manufacturing processes involving technical ceramics currently rely on the indirect process of fusing ceramic particles together with polymers or other binders. The parts require extensive post-processing, which includes moisture removal and binder or polymer burn out, followed by a traditional furnace sintering. Binder burn out for large or thick parts is particularly challenging and time consuming.
Additive manufacturing by selective laser sintering or selective laser melting of ceramics is also limited by cracking due to thermal and shrinkage stresses in the manufacturing process.
Accordingly, there is a need in the art for improved systems and methods for manufacturing ceramic parts using additive manufacturing.